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Linux File System
What is the purpose of file system Think of file system as a closet. Each slot in the closet is used to store jackets, socks, t-shirts etc. this makes the closet clean and not cluttered. Same is the purpose of the file system. Disk and Partitions: Partition are different blocks in a disk. We use…
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Linux inodes and Links
What is inode ? Each inode provides a unique identifier for each file and directory on the filesystem. When a file is created, it is assigned an inode number, which is unique within the filesystem. This allows the system to manage files by their inode numbers rather than by their names, which can be changed…
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Leetcode: Data Parsing
937. Reorder Data in Log Files Solution 1: Solution 2: 1st watch how sorted function works in python: https://www.youtube.com/watch?v=D3JvDWO-BY4 2 log files were shared and asked to write program to create a report based on aggregated values of parsed input
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RegEx
https://www.youtube.com/watch?v=sa-TUpSx1JA Meta Characters Meta Character Meaning of the meta character when searching . (dot) any character except new line \d any digit: 0-9 \D not a digit(0-9) \w any word character: a-z, A-Z,0-9, _ \W not word character \s whitespace: space, tab, newline \S not whitespace Anchors: don’t match character but match invisible position before/after…
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Networking IPv6
IPv6 replaces the 32-bit IPv4 address with a 128-bit address.128-bit IPv6 addresses are represented by breaking them up into eight 16-bit segments. Each segment is written in hexadecimal between 0x0000 and 0xFFFF, separated by colons. An example of a written IPv6 address is 3ffe:1944:0100:000a:0000:00bc:2500:0d0b. IPv6 Header: IPv6 types: ICMPv6: Used for various purpose. The Path…
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Networking: TCP
MTU: MSS: Now how MTU affects GRE or VxLAN or any other tunnelling ? TCP and MTU: TCP recognize Ethernet MTU and can calculate MSS from it. which means, if we set our Ethernet MTU as 9000, TCP will calculate MSS as 8960 bytes.in datacenter, we usually set MTU as 9000 bytes as we control…
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Networking Basics
We will go through the basic concepts in the networking in the blog. We will discuss about ARP, Proxy ARP, G ARP, NAT, NAT vs PAT, DHCP, ICMP, Traceroute, MTU, MTU vs MSS, PMTU etc. We start with the IPv4(20 bytes) and IPv6 header(40 Bytes) to understand why we need ARP in IPv4 and not…
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Neetcode: Array and Hashing
Problem 1: Contains Duplicate Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct. Problem 2: Valid Anagram Given two strings s and t, return true if t is an anagram of s, and false otherwise. An Anagram is a…
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Linux User Management
In Linux, users can be categorised into 3 general categories:
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Linux Basics
https://www.youtube.com/watch?v=UCr04qIB7uc What is Linux? Linux Distributions Family: Linux distribution: When a kernel is bundled with the operating system software and bundled together, that is called Linux distribution. Kernel: Distribution: Bootloader: Services: a program which runs as the background: Filesystem: Method for storing and organising files: Shell: Command line interpreter that interprets the command line input…